Table 3.
Predicted change in mean outcomes between 12 months and 24 months
|
12-month follow-up |
24-month follow-up |
Predicted change over long–term follow–up period | |||
|---|---|---|---|---|---|
| Predicted mean (95% CI) or log odds (95% CI) | Odds (95% CI) | Predicted mean (95% CI) or log odds (95% CI) | Odds (95% CI) | ||
| IBS-SSS | |||||
| Telephone-CBT group | 146·9 (122·7 to 171·0) | .. | 161·0 (140·2 to 181·9) | .. | 14·1 |
| Web-CBT group | 173·7 (155·3 to 192·2) | .. | 188·6 (169·9 to 207·2) | .. | 14·9 |
| TAU group | 209·1 (192·5 to 225·8) | .. | 201·5 (182·7 to 220·3) | .. | −7·6 |
| WSAS | |||||
| Telephone-CBT group | 7·2 (6·0 to 8·5) | .. | 7·0 (5·6 to 8·4) | .. | −0·2 |
| Web-CBT group | 7·8 (6·6 to 9·1) | .. | 8·2 (6·9 to 9·5) | .. | 0·4 |
| TAU group | 10·7 (9·5 to 11·9) | .. | 10·1 (8·8 to 11·4) | .. | −0·6 |
| HADS | |||||
| Telephone-CBT group | 12·5 (11·4 to 13·5) | .. | 12·5 (11·3 to 13·8) | .. | 0·0 |
| Web-CBT group | 13·0 (12·1 to 14·0) | .. | 13·0 (11·7 to 14·3) | .. | 0·0 |
| TAU group | 15·2 (14·2 to 16·2) | .. | 15·7 (14·5 to 16·8) | .. | 0·5 |
| PEQ | |||||
| Telephone-CBT group | 1·08 (0·41 to 1·75)* | 2·68 (1·37 to 2.95) | 1·11 (0·55 to 1·66) | 3·02 (1·73 to 5·28) | 0·03† |
| Web-CBT group | 0·11 (−0·29 to 0·51) | 1·02 (0·52 to 1·12) | 0·18 (−0·24 to 0·60) | 1·20 (0·79 to 1·82) | 0·07† |
| TAU group | −1·16 (−1·59 to −0·72) | 0·29 (0·15 to 0·31) | −1·01 (−1·47 to −0·55) | 0·36 (0·23 to 0·58) | 0·15† |
Data are predicted mean (95% CI) for IBS-SSS, WSAS, and HADs and log odds (95% CI) and odds (95% CI) for PEQ. Predictions are for sample average values of baseline variables (265 for IBS-SSS, 12·5 for WSAS, and 16·4 for HADS) and for the site from which most participants were recruited (general practices in Southampton). IBS-SSS=Irritable Bowel Syndrome Symptom Severity Score. CBT=cognitive behavioural therapy. TAU=treatment as usual. WSAS=Work and Social Adjustment Scale. HADS=Hospital Anxiety and Depression Scale. PEQ=Patient Enablement Questionnaire.
For the telephone-CBT group at the 12-month follow-up, therapist effects were found to be significant and were included in the model; the log odds presented here are conditional effects (conditioned on therapist in the telephone-CBT group).
Difference in log odds.